Needing plaster ceiling advise

Hello all!
As the bathroom remodel progresses, I hit a snag and am not sure what to do...any advice is appreciated...

The shower ceiling at 8 feet high is original plaster over metal netting and cement (?). (I'm sure I am using the wrong terms here)...I wanted to keep the original plaster finish.

After removing the old wall tile, and everything down to the studs, then placing a vapor barrier and Durcock, I noticed that where the wall meets the ceiling there is still a 1 inch gap where the finished plaster of the ceiling does not meet the new wall. The gap is bigger than the new tile will cover.

Any suggestions about what to use to fill in the gap between the original ceiling's plaster and the new wall?

I did the same thing with my remodel. I am a total DIY'er. Maybe someone else has a better idea.

I kept the plaster ceiling too, though it was wood lath and plaster, and filled the periphery void with a plastic type corner bead with synthetic mesh paper. I used durabond to mud the seams.

Here are some of my pictures.

Hole from the old vent stack that I repaired using plastic lath and durabond. Not your issue but you can see the gap to the right of the hole that was all around the room:

Process of the repair:

Ceiling gap process using the corner tape that is plastic. I might have pre filled the gap with durabond to close the gap before I put up the tape. Keep the durabond below the surface if you do this. One of my hole repair pictures looks like I might have prefilled the gap prior to taping the periphery of the room: